]>
git.proxmox.com Git - mirror_ubuntu-jammy-kernel.git/blob - include/linux/rbtree.h
3 (C) 1999 Andrea Arcangeli <andrea@suse.de>
5 This program is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation; either version 2 of the License, or
8 (at your option) any later version.
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
15 You should have received a copy of the GNU General Public License
16 along with this program; if not, write to the Free Software
17 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
19 linux/include/linux/rbtree.h
21 To use rbtrees you'll have to implement your own insert and search cores.
22 This will avoid us to use callbacks and to drop drammatically performances.
23 I know it's not the cleaner way, but in C (not in C++) to get
24 performances and genericity...
26 See Documentation/rbtree.txt for documentation and samples.
29 #ifndef _LINUX_RBTREE_H
30 #define _LINUX_RBTREE_H
32 #include <linux/kernel.h>
33 #include <linux/stddef.h>
34 #include <linux/rcupdate.h>
37 unsigned long __rb_parent_color
;
38 struct rb_node
*rb_right
;
39 struct rb_node
*rb_left
;
40 } __attribute__((aligned(sizeof(long))));
41 /* The alignment might seem pointless, but allegedly CRIS needs it */
44 struct rb_node
*rb_node
;
48 * Leftmost-cached rbtrees.
50 * We do not cache the rightmost node based on footprint
51 * size vs number of potential users that could benefit
52 * from O(1) rb_last(). Just not worth it, users that want
53 * this feature can always implement the logic explicitly.
54 * Furthermore, users that want to cache both pointers may
55 * find it a bit asymmetric, but that's ok.
57 struct rb_root_cached
{
58 struct rb_root rb_root
;
59 struct rb_node
*rb_leftmost
;
62 #define rb_parent(r) ((struct rb_node *)((r)->__rb_parent_color & ~3))
64 #define RB_ROOT (struct rb_root) { NULL, }
65 #define RB_ROOT_CACHED (struct rb_root_cached) { {NULL, }, NULL }
66 #define rb_entry(ptr, type, member) container_of(ptr, type, member)
68 #define RB_EMPTY_ROOT(root) (READ_ONCE((root)->rb_node) == NULL)
70 /* 'empty' nodes are nodes that are known not to be inserted in an rbtree */
71 #define RB_EMPTY_NODE(node) \
72 ((node)->__rb_parent_color == (unsigned long)(node))
73 #define RB_CLEAR_NODE(node) \
74 ((node)->__rb_parent_color = (unsigned long)(node))
77 extern void rb_insert_color(struct rb_node
*, struct rb_root
*);
78 extern void rb_erase(struct rb_node
*, struct rb_root
*);
81 /* Find logical next and previous nodes in a tree */
82 extern struct rb_node
*rb_next(const struct rb_node
*);
83 extern struct rb_node
*rb_prev(const struct rb_node
*);
84 extern struct rb_node
*rb_first(const struct rb_root
*);
85 extern struct rb_node
*rb_last(const struct rb_root
*);
87 extern void rb_insert_color_cached(struct rb_node
*,
88 struct rb_root_cached
*, bool);
89 extern void rb_erase_cached(struct rb_node
*node
, struct rb_root_cached
*);
90 /* Same as rb_first(), but O(1) */
91 #define rb_first_cached(root) (root)->rb_leftmost
93 /* Postorder iteration - always visit the parent after its children */
94 extern struct rb_node
*rb_first_postorder(const struct rb_root
*);
95 extern struct rb_node
*rb_next_postorder(const struct rb_node
*);
97 /* Fast replacement of a single node without remove/rebalance/add/rebalance */
98 extern void rb_replace_node(struct rb_node
*victim
, struct rb_node
*new,
99 struct rb_root
*root
);
100 extern void rb_replace_node_rcu(struct rb_node
*victim
, struct rb_node
*new,
101 struct rb_root
*root
);
102 extern void rb_replace_node_cached(struct rb_node
*victim
, struct rb_node
*new,
103 struct rb_root_cached
*root
);
105 static inline void rb_link_node(struct rb_node
*node
, struct rb_node
*parent
,
106 struct rb_node
**rb_link
)
108 node
->__rb_parent_color
= (unsigned long)parent
;
109 node
->rb_left
= node
->rb_right
= NULL
;
114 static inline void rb_link_node_rcu(struct rb_node
*node
, struct rb_node
*parent
,
115 struct rb_node
**rb_link
)
117 node
->__rb_parent_color
= (unsigned long)parent
;
118 node
->rb_left
= node
->rb_right
= NULL
;
120 rcu_assign_pointer(*rb_link
, node
);
123 #define rb_entry_safe(ptr, type, member) \
124 ({ typeof(ptr) ____ptr = (ptr); \
125 ____ptr ? rb_entry(____ptr, type, member) : NULL; \
129 * rbtree_postorder_for_each_entry_safe - iterate in post-order over rb_root of
130 * given type allowing the backing memory of @pos to be invalidated
132 * @pos: the 'type *' to use as a loop cursor.
133 * @n: another 'type *' to use as temporary storage
134 * @root: 'rb_root *' of the rbtree.
135 * @field: the name of the rb_node field within 'type'.
137 * rbtree_postorder_for_each_entry_safe() provides a similar guarantee as
138 * list_for_each_entry_safe() and allows the iteration to continue independent
139 * of changes to @pos by the body of the loop.
141 * Note, however, that it cannot handle other modifications that re-order the
142 * rbtree it is iterating over. This includes calling rb_erase() on @pos, as
143 * rb_erase() may rebalance the tree, causing us to miss some nodes.
145 #define rbtree_postorder_for_each_entry_safe(pos, n, root, field) \
146 for (pos = rb_entry_safe(rb_first_postorder(root), typeof(*pos), field); \
147 pos && ({ n = rb_entry_safe(rb_next_postorder(&pos->field), \
148 typeof(*pos), field); 1; }); \
151 #endif /* _LINUX_RBTREE_H */